All-solid secondary battery and method of manufacturing all-solid secondary battery

ABSTRACT

An all-solid secondary battery and a method of manufacturing the all-solid secondary battery. The all-solid secondary battery includes: an anode including an anode current collector and a first anode active material layer; a cathode including a cathode active material layer; and a solid electrolyte layer between the anode and the cathode, wherein the first anode active material layer includes an anode active material and an ionic compound, the ionic compound includes a binary compound, a ternary compound, or a combination thereof, and the ionic compound does not include a plurality of sulfur (S) atoms.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2018-0156273, filed on Dec. 6, 2018, in the KoreanIntellectual Property Office, and Korean Patent Application No.10-2019-0134804, filed on Oct. 28, 2019, in the Korean IntellectualProperty Office, and all the benefits accruing therefrom under 35 U.S.C.§ 119, the content of which is incorporated herein in its entirety byreference.

BACKGROUND 1. Field

The present disclosure relates to an all-solid secondary battery and amethod of manufacturing the all-solid secondary battery.

2. Description of the Related Art

Batteries having high energy density and high safety may be developed inaccordance with industrial standards. For example, lithium ion batteriesmay be used in the automotive field as well as in the fields ofinformation-associated equipment and communication equipment. In theautomotive field, safety of batteries is particularly important.

A lithium ion battery may use a liquid electrolyte including a flammableorganic solvent, and thus there may be a risk of overheating and fireshould a short circuit occur.

SUMMARY

Provided is an all-solid secondary battery having improved cyclecharacteristics due to suppression of side reactions of a solidelectrolyte between an anode layer and a solid electrolyte layer, and amethod of manufacturing the all-solid secondary battery.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

According to an aspect of an embodiment, an all-solid secondary batteryincludes: an anode including an anode current collector and a firstanode active material layer; a cathode including a cathode activematerial layer; and a solid electrolyte layer between the anode and thecathode, wherein the first anode active material layer includes an anodeactive material and an ionic compound, the ionic compound includes abinary compound, a ternary compound, or a combination thereof, and theionic compound does not include a plurality of sulfur (S) atoms.

According to an aspect of an embodiment, a method of manufacturing anall-solid secondary battery includes: providing an anode; providing acathode; and providing a solid electrolyte layer between the anode andthe cathode to thereby prepare a laminate; and pressing the laminate tomanufacture the all-solid secondary battery, wherein the anode includesan anode current collector and a first anode active material layer, thefirst anode active material layer includes an anode active material andan ionic compound, the ionic compound includes a binary compound, aternary compound, or a combination thereof, and the ionic compound doesnot include a plurality of sulfur (S) atoms.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings in which:

FIG. 1 is a cross-sectional view of an embodiment of an all-solidsecondary battery;

FIG. 2 is a cross-sectional view of an embodiment of an all-solidsecondary battery; and

FIG. 3 is a cross-sectional view of an embodiment of an all-solidsecondary battery.

DETAILED DESCRIPTION

The present disclosure will now be described more fully with referenceto the accompanying drawings, in which example embodiments are shown.The present disclosure may, however, be embodied in many differentforms, should not be construed as being limited to the embodiments setforth herein, and should be construed as including all modifications,equivalents, and alternatives within the scope of the presentdisclosure; rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will fully convey theeffects and features of the present disclosure and ways to implement thedisclosure to those skilled in the art.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentdisclosure. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof. As used herein, the slash“/” or the term “and/or” includes any and all combinations of one ormore of the associated listed items.

In the drawings, the size or thickness of each layer, region, or elementare arbitrarily exaggerated or reduced for better understanding or easeof description, and thus the present disclosure is not limited thereto.Throughout the written description and drawings, like reference numbersand labels will be used to denote like or similar elements. It will alsobe understood that when an element such as a layer, a film, a region ora component is referred to as being “on” another layer or element, itcan be “directly on” the other layer or element, or intervening layers,regions, or components may also be present. Although the terms “first”,“second”, etc., may be used herein to describe various elements,components, regions, and/or layers, these elements, components, regions,and/or layers should not be limited by these terms. These terms are usedonly to distinguish one component from another, not for purposes oflimitation. In the following description and drawings, constituentelements having substantially the same functional constitutions areassigned like reference numerals, and overlapping descriptions will beomitted.

“About” as used herein is inclusive of the stated value and means withinan acceptable range of deviation for the particular value as determinedby one of ordinary skill in the art, considering the measurement inquestion and the error associated with measurement of the particularquantity (i.e., the limitations of the measurement system). For example,“about” can mean within one or more standard deviations, or within ±30%,20%, 10% or 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

As used herein, a C rate means a current which will discharge a batteryin one hour, e.g., a C rate for a battery having a discharge capacity of1.6 ampere-hours would be 1.6 amperes.

As used herein, the term “ionic compound” refers to a chemical compoundincluding ions agglomerated by an electrostatic force called an ionicbond. The ionic compound may consist of cations and anions.

As used herein, the term “binary compound” refers to a compoundconsisting of two different elements. The binary compound may be, forexample, a compound represented by AB or A₂B, wherein A may be a cation,and B may be an anion.

As used herein, the term “ternary compound” refers to a compoundconsisting of three different elements. The ternary compound may be, forexample, a compound represented by A₂BX₄ or ABX₄, wherein A may be acation, B may be a cation or an anion, and X may be an anion.

As used herein, the term “inorganic compound” refers to a compound whichdoes not include a carbon-hydrogen (C—H) bond or a carbon-halogen (C—X,wherein X is F, Cl, Br, or I) bond, i.e., a non-organic compound.

As used herein, the term “crystalline compound” refers to a compoundhaving a highly ordered microscopic structure of constituent elements.The highly ordered microscopic structure may form a crystal latticeextending in all directions. The crystalline compound may exhibit a peakcorresponding to a structure of the crystal lattice in X-ray diffraction(“XRD”) spectra thereof. The crystalline compound is a solid.

As used herein, the term “amorphous compound” refers to a compound inwhich constituent atoms are irregularly arranged without an alignedmicrostructure. The amorphous compound does not form a crystal lattice.For example, in an XRD spectrum of the amorphous compound, a peakcorresponding to a crystal lattice structure may not appear.

As used herein, the term “average particle diameter” of particles maymeans an average particle diameter when the particles are spherical ormay means, when the particles are non-spherical, an average diameter ofspheres having the same volume as the non-spherical particles. Theaverage diameter may be a median diameter (D50), which is defined as aparticle diameter corresponding to 50% in a cumulative distributioncurve, i.e., which a particle diameter of 50% of particles is less than.The “50%” is on the basis of volume. The average particle diameter ofparticles may be measured using a particle size analyzer (PSA).

As used herein, the term “ionic radii” of anions may be measured usingX-ray diffraction (“XRD”).

An all-solid battery uses a solid electrolyte instead of a liquidelectrolyte. An all-solid battery may not use a flammable organicsolvent, and may have a reduced risk of fire or explosion should a shortcircuit occur. Accordingly, the all-solid battery may have increasedsafety as compared with a lithium ion battery using a liquidelectrolyte.

An all-solid battery may not exhibit good cycle characteristics due toside reactions resulting from oxidation and reduction of a solidelectrolyte between an anode layer and a solid electrolyte layer duringcharge and discharge processes.

An all-solid battery may use a solid electrolyte which may beelectrochemically stable during charge and discharge processes. A solidelectrolyte may have high mechanical intensity, high chemical stability,or a combination thereof, but a high temperature, high pressure, or acombination thereof may be used for sintering powder of the solidelectrolyte. For example, a high temperature of 1,000° C. or greater maybe used for sintering oxide-based solid electrolyte powder.

Hereinafter, embodiments of an all-solid secondary battery and a methodof manufacturing an all-solid secondary battery will be described ingreater detail.

According to an aspect of the disclosure, an all-solid secondary batteryincludes: an anode, e.g., an anode layer, including an anode currentcollector and a first anode active material layer; a cathode, e.g., acathode layer, including a cathode active material layer; and a solidelectrolyte layer between the anode layer and the cathode layer, whereinthe first anode active material layer includes an anode active materialand an ionic compound, the ionic compound includes a binary compound, aternary compound, or a combination thereof, and the ionic compound doesnot include a plurality of sulfur (S) atoms.

Since the first anode active material layer includes the ionic compound,a side reaction of a solid electrolyte between the first anode activematerial layer and the solid electrolyte layer may be suppressed, andconsequently the all-solid secondary battery may have improved cyclecharacteristics. By the inclusion of the ionic compound in the firstanode active material layer, the first anode active material layer mayhave improved electrochemical stability, and thus the solid electrolytelayer in contact with the first anode active material layer may haveimproved stability. For example, by the inclusion of the ionic compoundin the first anode active material layer, the first anode activematerial layer may serve as a kind of an artificial solid electrolyteinterface film. For example, due to the inclusion of the ionic compoundin the first anode active material layer, a solid electrolyte interface(“SEI”) film formed between the first anode active material layer andthe solid electrolyte layer during charge and discharge may have a morestable structure, as compared with a SEI film generated in a comparativeall-solid secondary battery.

Referring to FIGS. 1 to 3, an all-solid secondary battery 1 according toan embodiments may include: an anode layer 20 including an anode currentcollector layer 21 and a first anode active material layer 22; a cathodelayer 10 including a cathode active material layer 12; and a solidelectrolyte layer 30 arranged between the anode layer 20 and the cathodelayer 10.

Anode Layer

Referring to FIGS. 1 to 3, the anode layer 20 may include the anodecurrent collector layer 21 and the first anode active material layer 22.The first anode active material layer 22 may include an anode activematerial and an ionic compound. The ionic compound may include a binarycompound, a ternary compound, or a combination thereof. The ioniccompound may not include a plurality of sulfur (S) atoms, i.e., two ormore sulfur (S) atoms. Ternary compounds and/or binary compoundsincluding two or more sulfur atoms, for example, P₂S₅, Li₃PS₄, Li₂P₂S₆,Li₇P₃S₁₁, Li₇PS₆, Li₄S₂P₆, or the like may be excluded from use as theionic compound.

The ionic compound of the first anode active material layer 22 may be,for example, an inorganic compound. Accordingly, the ionic compound isdistinguished from an organic binder such as an ionic polymer. The ioniccompound may be an electrochemically inert compound. Accordingly, theionic compound is distinguished from an anode active material havingelectrochemical activity such as Li₄Ti₅O₁₂.

The ionic compound included in the first anode active material layer 22may be, for example, a crystalline compound. For example, the binarycompound may have a crystal structure such as a rocksalt-type structure,a wurtzite-type structure, an antifluorite structure, or a hexagonalstructure. The ternary compound may have a crystal structure such as anantiperovskite-type structure, a layered-type structure, a spinel-typestructure, or a trigonal structure. LiCl may have a crystal structure,for example, a rocksalt-type structure or a wurtzite-type structure. Inan embodiment, the ionic compound may be an amorphous compound. Forexample, LiCl may form an amorphous phase.

The ionic compound included in the first anode active material layer 22may be, for example, a metal salt compound including a metal cation. Ametal element of the metal salt compound may include, for example, analkali metal element such as Li, Na, or K. For example, the ioniccompound may be a lithium salt compound including a lithium element. Thelithium salt compound is an ionic compound including a lithium cation.Accordingly, binary compounds or ternary compounds not including alithium element, for example, Al₂O₃, SiO₂, TiO₂, BaTiO₃, or the like areexcluded from use as the ionic compound.

Anions of the lithium salt compound included in the first anode activematerial layer 22 may have an ionic radius of, for example, about 0.40nanometers (nm) or less, about 0.35 nm or less, about 0.30 nm or less,about 0.25 nm or less, or about 0.20 nm or less. Anions of the lithiumsalt compound included in the first anode active material layer 22 mayhave an ionic radius of, for example, about 0.001 nm or greater, about0.01 nm or greater, or about 0.1 nm or greater. When the anions of thelithium salt compound have an ionic radius within these ranges, sidereactions with the solid electrolyte may be suppressed, or a solidelectrolyte interface film resulting from reaction with the solidelectrolyte may have improved stability. For example, F anions may havean ionic radius of about 0.136 nm, CI anions may have an ionic radius ofabout 0.181 nm, Br anions may have an ionic radius of about 0.196 nm,and I anions may have an ionic radius of about 0.216 nm. In contrast,bis(trifluoromethanesulfonyl)imide (“TFSI”) anions may have an ionicradius of about 0.439 nm. The ionic radius may be an atomic radius orthermochemical radius in an ionic crystal structure.

For example, the lithium salt compound of the first anode activematerial layer 22 may include at least one binary compound such as LiF,LiCl, LiBr, LiI, LiH, Li₂S, Li₂O, Li₂Se, Li₂Te, Li₃N, Li₃P, Li₃As,Li₃Sb, or Li₃B; at least one ternary compound such as Li₃OCl, LiPF₆,LiBF₄, LiSbF₆, LiAsF₆, LiClO₄, LiAlO₂, LiAlCl₄, LiNO₃, Li₂CO₃, LiBH₄,Li₂SO₄, Li₃BO₃, Li₃PO₄, Li₄NCl, Li₅NCl₂, or Li₃BN₂; or a combinationthereof. For example, the lithium salt compound may be a lithium halidecompound such as LiF, LiCl, LiBr, LiI, or a combination thereof.

The lithium salt compound in the first anode active material layer 22may be present independently, not as a composite with sulfide or othercompounds. This lithium salt compound is distinguished from a lithiumsalt compound used as a precursor in preparation of a solid electrolytesuch as a sulfide-based solid electrolyte and constituting part of thesolid electrolyte. For example, LiCl of a Li₂S—SiS₂—LiCl composite isdistinguished from the lithium salt compound of the first anode activematerial layer 22.

An amount of the ionic compound in the first anode active material layer22 may be, for example, about 3 weight percent (wt %) to about 80 wt %,about 3 wt % to about 50 wt %, about 3 wt % to about 30 wt %, about 3 wt% to about 25 wt %, about 3 wt % to about 20 wt %, about 5 wt % to about20 wt %, about 7 wt % to about 15 wt %, or about 7 wt % to about 13 wt%, based on a total weight of the first anode active material layer 22.When the amount of the ionic compound in the first anode active materiallayer 22 is within these ranges, the all-solid secondary battery 1 mayhave further improved cycle characteristics. When the amount of theionic compound is excessively small, a cycle characteristics improvementeffect may be negligible. When the amount of the ionic compound isexcessive, the amount of the anode active material may become relativelysmall, so that the first anode active material layer may not functionproperly. Furthermore, due to increased growth of lithium dendrite, theall-solid electrolyte battery 1 may have poor cycle characteristics.When the amount of the ionic compound is 50 wt % or greater, the ioniccompound may be partially precipitated from the slurry including theionic compound, so that processability in preparing and coating theslurry including the ionic compound may be partially deteriorated. Forexample, film characteristic of the first anode active material layer 22may become partially non-uniform. Accordingly, the amount of the ioniccompound included in the first anode active material layer 22 may be,for example, about 3 wt % to less than about 50 wt %, about 3 wt % toabout 30 wt %, or about 7 wt % to about 13 wt %.

The anode active material of the first anode active material layer 22may be, for example, in the form of particles. For example, the anodeactive material in the form of particles may have an average particlediameter of 4 micrometers (μm) or less, about 3 μm or less, about 2 μmor less, about 1 μm or less, or about 900 nm or less. For example, theanode active material in the form of particles may have an averageparticle diameter of about 10 nm to about 4 μm, about 10 nm to about 3μm, about 10 nm to about 2 μm, about 10 nm to about 1 μm, or about 10 nmto about 900 nm. When the anode active material has an average particlediameter within these ranges, reversible absorption, desorption, or acombination thereof of lithium during charge and discharge may befurther facilitated. The average particle diameter of the anode activematerial may be a median diameter (D50) obtained using, for example, alaser-diffraction particle size distribution analyzer.

For example, the anode active material of the first anode activematerial layer 22 may further include a carbonaceous anode activematerial; a metal, metalloid anode active material, or a combinationthereof; or a combination thereof.

The carbonaceous anode active material may be, for example, amorphouscarbon. For example, the amorphous carbon may be carbon black (“CB”),acetylene black (“AB”), furnace black (“FB”), ketjen black (“KB”), orgraphene. However, embodiments are not limited thereto. Any suitableamorphous carbons may be used. The amorphous carbon refers to carbonwithout crystallinity or with very low crystallinity, and isdistinguished from crystalline carbon or graphitic carbon.

The metal, metalloid anode active material, or a combination thereof mayinclude gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver(Ag), aluminum (Al), bismuth (Bi), tin (Sn), antimony (Sb), magnesium(Mg), zinc (Zn), or a combination thereof. However, embodiments are notlimited thereto. Any suitable metal anode active material, metalloidanode active material, or combination thereof capable of forming analloy or compound with lithium may be used. For example, nickel (Ni),which does not form an alloy with lithium, may not be used as the metalanode active material.

The first anode active material layer 22 may include one of theabove-listed anode active materials or a mixture of at least two of theabove-listed anode active materials. For example, the first anode activematerial layer 22 may include only amorphous carbon alone, or gold (Au),platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al),bismuth (Bi), tin (Sn), antimony (Sb), magnesium (Mg), zinc (Zn), or acombination thereof. In an embodiment, the first anode active materiallayer 22 may include a mixture of amorphous carbon and gold (Au),platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al),bismuth (Bi), tin (Sn), antimony (Sb), magnesium (Mg), zinc (Zn), or acombination thereof. In the mixture of the amorphous carbon and a metal,metalloid, or a combination thereof, a mixed ratio of the amorphouscarbon to the metal, metalloid, or a combination thereof may be, forexample, about 10:1 to about 1:2, about 5:1 to about 1:1, or about 4:1to about 2:1 in weight ratio. However, embodiments are not limitedthereto. The mixed ratio may be appropriately chosen according todesired characteristics of the all-solid secondary battery 1. Sincefirst anode active material layer 22 has a composition as describedabove, the all-solid secondary battery 1 may have further improved cyclecharacteristics.

The anode active material of the first anode active material layer 22may include a mixture of first particles including, e.g., consisting of,amorphous carbon and second particles including, e.g., consisting of, ametal, metalloid, or combination thereof. Examples of the metal,metalloid, or combination thereof may be gold (Au), platinum (Pt),palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi),tin (Sn), antimony (Sb), magnesium (Mg), and zinc (Zn). For example, themetalloid may be a semiconductor. The amount of the second particles maybe about 8 wt % to about 60 wt %, about 10 wt % to about 50 wt %, about15 wt % to about 40 wt %, or about 20 wt % to about 30 wt %, based on atotal weight of the mixture. When the amount of the second particles iswithin these ranges, the all-solid secondary battery 1 may have furtherimproved cycle characteristics.

The first anode active material layer 22 may include, for example, abinder. The binder may be, for example, a styrene-butadiene rubber(“SBR”), polytetrafluoroethylene (“PTFE”), polyvinylidene fluoride(“PVDF”), polyethylene, a vinylidene fluoride/hexafluoropropylenecopolymer, polyacrylonitrile, or polymethylmethacrylate. However,embodiments are not limited thereto. Any suitable binder may be used.The binder may be one binder or include a plurality of differentbinders. The first anode active material layer 22 may include a surface22 a contacting the solid electrolyte layer 30.

By the inclusion of the binder, the first anode active material layer 22may be stabilized on the anode current collector 21. In addition,cracking of the first anode active material layer 22 may be suppressedin spite of volume change, relative position change, or a combinationthereof of the first anode active material layer 22 during charge anddischarge processes. For example, when the first anode active materiallayer 22 does not include such a binder, the first anode active materiallayer 22 may be easily separated from the anode current collector 21.When a portion of the first anode active material layer 22 is separatedfrom the anode current collector 21, the anode current collector 21 maybe partially exposed to contact with the solid electrolyte layer 30, andaccordingly, a short-circuit may more likely occur. For example, thefirst anode active material layer 22 may be formed by coating, on theanode current collector 21, a slurry in which ingredients of the firstanode active material layer 22 are dispersed, and then drying theresulting product. By inclusion of the binder in the first anode activematerial layer 22, the anode active material may be stably dispersed inthe slurry. For example, when the slurry is coated on the anode currentcollector 21 by using screen printing, clogging of the screen (forexample, clogging by aggregates of the anode active material) may besuppressed.

For example, a thickness d22 of the first anode active material layer 22may be about 50% or less, about 40% or less, about 30% or less, about20% or less, about 10% or less, or about 5% or less of a thickness ofthe cathode active material layer. For example, the thickness d22 of thefirst anode active material layer 22 may be about 1 μm to about 20 μm,about 2 μm to about 10 μm, or about 3 μm to about 7 μm. When thethickness d22 of the first anode active material layer 22 is too thin,the first anode active material layer 22 may be disintegrated by lithiumdendrites generated between the first anode active material layer 22 andthe anode current collector 21, which may deteriorate cyclecharacteristics of the all-solid secondary battery 1. When the thicknessd22 of the first anode active material layer 22 is too thick, theall-solid secondary battery 1 may have a reduced energy density, anincreased internal resistance, and thus poor cycle characteristics.

When the thickness d22 of the first anode active material layer 22 isreduced, for example, the first anode active material layer 22 may havea reduced charge capacity. For example, a charge capacity of the firstanode active material layer 22 may be about 50% or less, about 40% orless, about 30% or less, about 20% or less, about 10% or less, about 5%or less, or about 2% or less of a charge capacity of the cathode activematerial layer 12, which has a thickness d12. For example, a chargecapacity of the first anode active material layer 22 may be about 0.1%to about 50%, about 0.1% to about 40%, about 0.1% to about 30%, about0.1% to about 20%, about 0.1% to about 10%, about 0.1% to about 5%, orabout 0.1% to about 2% of a charge capacity of the cathode activematerial layer 12. When the charge capacity of the first anode activematerial layer 22 is too small, the thickness of the first anode activematerial layer 22 may become so thin that the first anode activematerial layer 22 may be disintegrated by lithium dendrites generatedbetween the first anode active material layer 22 and the anode currentcollector during repeated charging and discharging processes, andconsequently the all-solid secondary battery 1 may have poor cyclecharacteristics. When the charge capacity of the first anode activematerial layer 22 is excessively increased, the all-solid secondarybattery 1 may have a reduced energy density, an increased internalresistance, and thus poor cycle characteristics.

The charge capacity of the cathode active material layer 12 may beobtained by multiplying a charge capacity density (milliampere hours pergram (mAh/g)) of a cathode active material in the cathode activematerial layer 12 by a mass of the cathode active material. Whendifferent cathode active materials are used, a charge capacity densityof each of the cathode active materials may be multiplied by a massthereof, and then the sum of the multiplication products may becalculated as the charge capacity of the cathode active material layer12. The charge capacity of the first anode active material layer 22 maybe calculated in the same manner. That is, the charge capacity of thefirst anode active material layer 22 may be obtained by multiplying acharge capacity density of an anode active material in the first anodeactive material layer 22 by a mass of the anode active material. When aplurality of different anode active materials are used, a chargecapacity density of each of the anode active materials may be multipliedby a mass thereof, and then the sum of the multiplication products maybe calculated as the charge capacity of the first anode active materiallayer 22. The charge capacity densities of the cathode active materialand the anode active material are estimated capacities obtained with anall-solid half-cell including lithium metal as a counter electrode. Thecharge capacities of the cathode active material layer 12 and the firstanode active material layer 22 may be directly calculated using anall-solid half-cell. The measured charge capacity of each of the cathodeand anode active materials may be divided by a mass of the correspondingactive material to thereby obtain the charge capacity density of theactive material. In an embodiment, the charge capacities of the cathodeactive material layer 12 and the first anode active material layer 22may be initial charge capacities measured after 1^(st) cycle charging.

For example, the anode current collector 21 may consist of a materialwhich does not react with lithium to form an alloy or compound. Thematerial of the anode current collector 21 may be, for example, copper(Cu), stainless steel (SUS), titanium (Ti), iron (Fe), cobalt (Co),nickel (Ni), or the like. However, embodiments are not limited thereto.Any suitable material as an anode current collector may be used. Theanode current collector 21 may include one of the above-listed metals oran alloy or a coated material of two or more of the above-listed metals.The anode current collector 12 may be, for example, in the form of aplate or a foil.

The first anode active material layer 22 of the all-solid secondarybattery 1 may further include an additive(s), for example, a filler, adispersing agent, an ionic conducting agent, or the like.

Referring to FIG. 2, in an embodiment, the all-solid secondary battery 1may further include a thin film 24 on the anode current collector 21,the thin film 24 including an element alloyable with lithium. The thinfilm 24 may be arranged between the anode current collector 21 and thefirst anode active material layer 22. The thin film 24 may include, forexample, an element alloyable with lithium. The element alloyable withlithium may be, for example, gold (Au), silver (Ag), zinc (Zn), tin(Sn), indium (In), silicon (Si), aluminum (Al), bismuth (Bi), magnesium(Mg), antimony (Sb), or the like. However, embodiments are not limitedthereto. Any suitable element which may form an alloy with lithium maybe used. The thin film 24 may consist of one of the above-listed metalsor metalloid or an alloy of two or more of the metals or metalloid. Dueto the arrangement of the thin film 24 on the anode current collector21, for example, a second anode active layer (not shown) disposedbetween the thin film 24 and the first anode active material layer 22may be further planarized, further improving cycle characteristics ofthe all-solid secondary battery 1.

A thickness d24 of the thin film 24 may be, for example, about 1 nm toabout 800 nm, about 10 nm to about 700 nm, about 50 nm to about 600 nm,or about 100 nm to about 500 nm. When the thickness d24 of the thin film24 is less than 1 nm, the thin film 24 may not function properly. Whenthe thickness d24 of the thin film 24 is too thick, the thin film 24 mayabsorb lithium, so that a precipitation of lithium on the anode may bereduced, which may consequently lower energy density of the all-solidsecondary battery 1 and deteriorate cycle characteristics thereof. Thethin film 24 may be formed on the anode current collector by using, forexample, a vapor deposition method, a sputtering method, a platingmethod, or the like. However, embodiments are not limited thereto. Anysuitable method capable of forming the thin film 24 may be used.

Referring to FIG. 3, in an embodiment, the all-solid secondary battery 1may further include a second anode active material layer 23 between theanode current collector 21 and the solid electrolyte layer 30. Forexample, the all-solid secondary battery 1 may further include thesecond anode active material layer disposed between the anode currentcollector 21 and the first anode active material layer 22 throughcharging. In an embodiment, although not illustrated, the all-solidsecondary battery 1 may further include a second anode active materiallayer disposed between the solid electrolyte layer 30 and the firstanode active material layer 22 through charging. In an embodiment,although not illustrated, the all-solid secondary battery 1 may furtherinclude a second anode active material layer deposited within the firstanode active material layer 22 through charging.

The second anode active material layer 23 may be a metal layer includinglithium, a lithium alloy, or a combination thereof. The metal layer mayinclude lithium, a lithium alloy, or a combination thereof. Since thesecond anode active material layer 23 is a metal layer includinglithium, the second anode active material layer 23 may function, forexample, as a lithium reservoir. The lithium alloy may be, for example,a Li—Al alloy, a Li—Sn alloy, a Li—In alloy, a Li—Ag alloy, a Li—Aualloy, a Li—Zn alloy, a Li—Ge alloy, a Li—Si alloy, a Li—Mg alloy, or aLi—Sb alloy. However, embodiments are not limited thereto. Any suitablelithium alloy may be used. The second anode active material layer 23 mayinclude a lithium alloy, lithium, or a combination thereof, or aplurality of different alloys.

A thickness d23 of the second anode active material layer 23 is notspecifically limited. For example, the thickness d23 of the second anodeactive material layer 23 may be about 1 μm to about 1,000 μm, about 1 μmto about 500 μm, about 1 μm to about 200 μm, about 1 μm to about 150 μm,about 1 μm to about 100 μm, or about 1 μm to about 50 μm. When thethickness d23 of the second anode active material layer 23 is too thin,the second anode active material layer 23 may not appropriately functionas a lithium reservoir. When the thickness d23 of the second anodeactive material layer 23 is too thick, the mass and volume of theall-solid secondary battery 1 may be increased, further deterioratingcycle characteristics. The second anode active material layer 23 may be,for example, a metal foil having a thickness within these ranges.

The second anode active material layer 23 of the all-solid secondarybattery 1 may, for example, be arranged between the anode currentcollector 21 and the first anode active material layer 22 beforeassembly of the all-solid secondary battery 1, or be precipitatedbetween the anode current collector 21 and the first anode activematerial layer 22 by charging after assembly of the all-solid secondarybattery 1.

When the second anode active material layer 23 is arranged between theanode current collector 21 and the first anode active material layer 22before assembly of the all-solid secondary battery, the second anodeactive material layer 23 as a metal layer including lithium may functionas a lithium reservoir. The all-solid secondary battery 1 including thesecond anode active material layer 23 may have further improved cyclecharacteristics. For example, a lithium foil as the second anode activematerial layer 23 may be arranged between the anode current collector 21and the first anode active material layer 22 before assembly of theall-solid secondary battery 1.

When the second active material layer 23 is deposited by charging afterassembly of the all-solid secondary battery 1, the all-solid secondarybattery 1 may have an increased energy density since the second anodeactive material layer 23 is not included in assembling the all-solidsecondary battery 1. For example, the all-solid secondary battery 1 maybe charged until a charge capacity of the first anode active materiallayer 22 is exceeded. That is, the first anode active material layer 22may be overcharged. At an initial charging stage, lithium may beabsorbed into the first anode active material layer 22. That is, theanode active material in the first anode active material layer 22 mayform an alloy or compound with lithium ions moved from the cathode layer10. When the all-solid secondary batter 1 is charged over the capacityof the first anode active material layer 22, for example, lithium may beprecipitated on a rear surface of the first anode active material layer22, i.e., between the anode current collector 21 and the first anodeactive material layer 22, thus forming a metal layer corresponding tothe second anode active material layer 23. The second anode activematerial layer 23 may be a metal layer including lithium (i.e., metallithium) as a major component. This may be attributed to, for example,the fact that the anode active material in the first anode activematerial layer 22 includes a material capable of forming an alloy orcompound with lithium. During discharge, lithium in the first anodeactive material layer 22 and the second anode active material layer 23,i.e., lithium metal layer, may be ionized and then move towards thecathode layer 10. Accordingly, the all-solid secondary battery 1 may uselithium as the anode active material. Since the first anode activematerial layer 22 coats the second anode active material layer 23, thefirst anode active material layer 22 may function as a protective layerof the second anode active material layer 23 and at the same timesuppress precipitation and growth of lithium dendrite. Accordingly, ashort-circuit and reduction in capacity of the all-solid secondarybattery 1 may be suppressed, and consequently cycle characteristics ofthe all-solid secondary battery 1 may be improved. When the second anodeactive material layer 23 is disposed through charging after assembly ofthe all-solid secondary battery 1, the anode current collector 21, thefirst anode active material layer 22, and a region therebetween may be,for example, Li-free regions which do not include lithium (Li) metal ora Li alloy in an initial state or a post-discharge state of theall-solid secondary battery.

Solid Electrolyte Layer

Referring to FIGS. 1 to 3, the solid electrolyte layer 30 may contain asolid electrolyte between the cathode layer 10 and the anode layer 20.

The solid electrolyte may be, for example, a sulfide-based solidelectrolyte. The sulfide-based solid electrolyte may be, for example,Li₂S—P₂S₅, Li₂S—P₂S₅—LiX (wherein X is a halogen), Li₂S—P₂S₅—Li₂O,Li₂S—SiS₂, Li₂S—SiS₂—LiI, Li₂S—SiS₂—LiBr, Li₂S—SiS₂—LiCl,Li₂S—SiS₂—B₂S₃—Li Li₂S—SiS₂—P₂S₅—Li Li₂S—B₂S₃, Li₂S—P₂S₅—Z_(m)S_(n)(wherein m and n are each independently a positive number, and Z is Ge,Zn, or Ga), Li₂S—GeS₂, Li₂S—SiS₂—Li₃PO₄, Li₂S—SiS₂-Li_(p)MO_(q) (whereinp and q are each independently a positive number, and M is P, Si, Ge, B,Al, Ga, or In), or a combination thereof. The sulfide-based solidelectrolyte may be prepared using a starting or source material, forexample, Li₂S, P₂S₅, or the like by melt quenching or mechanicalmilling, after which thermal treatment may further be performed. Thesolid electrolyte may be amorphous, crystalline, or a mixed statethereof.

The solid electrolyte may be, for example, any of the above-listedsulfide-based solid electrolyte materials including at least sulfur (S),phosphorous (P), and lithium (Li) as constituent elements. For example,the solid electrolyte may be a material including Li₂S—P₂S₅. When thesolid electrolyte includes Li₂S—P₂S₅ as a sulfide-based solidelectrolyte material, a mixed mole ratio of Li₂S to P₂S₅ (Li₂S:P₂S₅) maybe, for example, in a range of about 50:50 to about 90:10.

For example, the sulfide-based solid electrolyte may include Li₇P₃S₁₁,Li₇PS₆, Li₄P₂S₆, Li₃PS₆, Li₃PS₄, Li₂P₂S₆, or a combination thereof.

The sulfide-based solid electrolyte may include, for example, anargyrodite-type solid electrolyte represented by Formula 1:

Li⁺ _(12-n-x)A^(n+)X²⁻ _(6-x)Y¹⁻ _(x)  Formula 1

In Formula 1, 0≤x≤2; A may be P, As, Ge, Ga, Sb, Si, Sn, Al, In, Ti, V,Nb, or Ta; X may be S, Se, or Te; Y′ may be Cl, Br, I, F, CN, OCN, SCN,or N₃; and n is a valence of A. In an embodiment, n may be 3, 4, or 5.

For example, the argyrodite-type solid electrolyte may includeLi_(7-x)PS_(6-x)Cl_(x) (wherein 0≤x≤2), Li_(7-x)PS_(6-x)Br_(x) (wherein0≤x≤2), Li_(7-x)PS_(6-x)I_(x) (wherein 0≤x≤2), or a combination thereof.For example, the argyrodite-type solid electrolyte may include Li₆PS₅Cl,Li₆PS₅Br, Li₆PS₅I, or a combination thereof.

For example, the solid electrolyte may have an elastic modulus, i.e.,Young's modulus, of about 35 gigapascals (GPa) or less, about 30 GPa orless, about 27 GPa or less, about 25 GPa or less, or about 23 GPa orless. For example, the solid electrolyte may have an elastic modulus,i.e., Young's modulus, of about 10 GPa to about 35 GPa, about 15 GPa toabout 30 GPa, or about 15 GPa to about 25 GPa. When the solidelectrolyte has an elastic modulus within these ranges, sintering of thesolid electrolyte may be facilitated.

For example, the solid electrolyte layer 30 may further include abinder. The binder included in the solid electrolyte layer 30 may be,for example, a styrene-butadiene rubber (“SBR”), polytetrafluoroethylene(“PTFE)”, polyvinylidene fluoride (“PVDF”), polyethylene, orpolyacrylate resin. However, embodiments are not limited thereto. Anysuitable binder may be used. The binder of the solid electrolyte layer30 may be the same as or different from the binders of the cathodeactive material layer 12 and the first anode active material layer 22.

Cathode Layer

The cathode layer 10 may include a cathode current collector 11 and thecathode active material layer 12.

The cathode current collector 11 may be a plate or foil including indium(In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron(Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium(Ge), lithium (Li), or an alloy thereof. The cathode current collector11 may be omitted.

The cathode active material layer 12 may include, for example, a cathodeactive material and a solid electrolyte. The solid electrolyte in thecathode layer 10 may be the same as or different from the solidelectrolyte of the solid electrolyte layer 30. Details of the solidelectrolyte may be the same as described above in connection with thesolid electrolyte layer 30.

The cathode active material may be a cathode active material capable ofabsorption and desorption of lithium ions. The cathode active materialmay be, for example, a lithium transition metal oxide, such as lithiumcobalt oxide (“LCO”), lithium nickel oxide, lithium nickel cobalt oxide,lithium nickel cobalt aluminum oxide (“NCA”), lithium nickel cobaltmanganese oxide (“NCM”), lithium manganate, or lithium iron phosphate;nickel sulfide; copper sulfide; lithium sulfide; iron oxide; or vanadiumoxide. However, embodiments are not limited thereto. Any suitablecathode active material may be used. One or more cathode activematerials may be used.

The cathode active material may be, for example, a compound representedby one of the following formula: Li_(a)A_(1-b)B′_(b)D₂ (wherein0.90≤a≤1, and 0≤b≤0.5); Li_(a)E_(1-b)B′_(b)O_(2-c)D_(c) (wherein0.90≤a≤1, 0≤b≤0.5, and 0≤c≤0.05); LiE_(2-b)B′_(b)O_(4-c)D_(c) (wherein0≤b≤0.5, and 0≤c≤0.05); Li_(a)Ni_(1-b-c)Co_(b)B′_(c)D_(a) (wherein0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, and 0<α≤2);Li_(a)Ni_(1-b-c)Co_(b)B′_(c)O_(2-α)F′_(α) (wherein 0.90≤a≤1, 0≤b≤0.5,0≤c≤0.05, and 0<α<2); Li_(a)Ni_(1-b-c)Co_(b)B′_(c)O_(2-α)F′₂ (wherein0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, and 0<α<2);Li_(a)Ni_(1-b-c)Mn_(b)B′_(c)D_(α) (wherein 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05,and 0<α≤2); Li_(a)Ni_(1-b-c)Mn_(b)B′_(c)O_(2-α)F′_(α) (wherein 0.90≤a≤1,0≤b≤0.5, 0≤c≤0.05, and 0<σ<2); Li_(a)Ni_(1-b-c)Mn_(b)B′_(c)O_(2-α)F′₂(wherein 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, and 0<α<2);Li_(a)Ni_(b)E_(c)G_(d)O₂ (wherein 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, and0.001≤d≤0.1); Li_(a)Ni_(b)Co_(c)Mn_(d)GeO₂ (wherein 0.90≤a≤1, 0≤b≤0.9,0≤c≤0.5, 0≤d≤0.5, and 0.001≤e≤0.1); Li_(a)NiG_(b)O₂ (wherein 0.90≤a≤1,and 0.001≤b≤0.1); Li_(a)CoG_(b)O₂ (wherein 0.90≤a≤1, and 0.001≤b≤0.1);Li_(a)MnG_(b)O₂ (wherein 0.90≤a≤1, and 0.001≤b≤0.1); Li_(a)Mn₂G_(b)O₄(wherein 0.90≤a≤1, and 0.001≤b≤0.1); QO₂; QS₂; LiQS₂; V₂O₅; LiV₂O₅;LiI′O₂; LiNiVO₄; Li_((3-f))J₂(PO₄)₃ (wherein 0≤f≤2); Li_((3-f))Fe₂(PO₄)₃(wherein 0≤f≤2); and LiFePO₄.

In the formulae above, A may be nickel (Ni), cobalt (Co), manganese(Mn), or a combination thereof; B′ may be aluminum (Al), nickel (Ni),cobalt (Co), manganese (Mn), chromium (Cr), iron (Fe), magnesium (Mg),strontium (Sr), vanadium (V), a rare earth element, or a combinationthereof; D may be oxygen (O), fluorine (F), sulfur (S), phosphorus (P),or a combination thereof; E may be cobalt (Co), manganese (Mn), orcombination thereof; F′ may be fluorine (F), sulfur (S), phosphorus (P),or a combination thereof; G may be aluminum (Al), chromium (Cr),manganese (Mn), iron (Fe), magnesium (Mg), lanthanum (La), cerium (Ce),strontium (Sr), vanadium (V), or a combination thereof; Q may betitanium (Ti), molybdenum (Mo), manganese (Mn), or a combinationthereof; I′ may be chromium (Cr), vanadium (V), iron (Fe), scandium(Sc), yttrium (Y), or a combination thereof; and J may be vanadium (V),chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), ora combination thereof.

The compounds listed above as cathode active materials may have asurface coating layer (hereinafter, also referred to as “coatinglayer”). A mixture of a compound listed above without a coating layerand a compound listed above having a coating layer may be used. In anembodiment, the coating layer on the surface of such compounds mayinclude a compound of a coating element such as an oxide, a hydroxide,an oxyhydroxide, an oxycarbonate, or a hydroxycarbonate of the coatingelement, or a combination thereof. In an embodiment, the compounds forthe coating layer may be amorphous or crystalline. In an embodiment, thecoating element for the coating layer may be magnesium (Mg), aluminum(Al), cobalt (Co), potassium (K), sodium (Na), calcium (Ca), silicon(Si), titanium (Ti), vanadium (V), tin (Sn), germanium (Ge), gallium(Ga), boron (B), arsenic (As), zirconium (Zr), or a combination thereof.In an embodiment, the coating layer may be formed using any suitablemethod that does not adversely affect the physical properties of thecathode active material. For example, the coating layer may be formedusing a spray coating method, a dipping method, or the like.

The cathode active material may include, for example a lithium salt of atransition metal oxide having a layered rocksalt-type structure amongthe above-listed lithium transition metal oxides. The term “layeredrocksalt-type structure” used herein refers to a structure in whichoxygen atomic layers and metal atomic layers are alternately regularlyarranged in the direction of <111> planes, with each atomic layerforming a 2-dimensional (“2D”) plane. A “cubic rocksalt-type structure”refers to a sodium chloride (NaCl)-type crystal structure, and inparticular, a structure in which face-centered cubic (“fcc”) latticesformed by respective cations and anions are arranged in a way thatridges of the unit lattices are shifted by ½. The lithium transitionmetal oxide having such a layered rocksalt-type structure may be, forexample, a ternary lithium transition metal oxide such asLiNi_(x)Co_(y)Al_(z)O₂ (“NCA”) or LiNi_(x)Co_(y)Mn_(z)O₂ (“NCM”)(wherein 0<x<1, 0<y<1, 0<z<1, and x+y+z=1). When the cathode activematerial includes such a ternary lithium transition metal oxide having alayered rocksalt-type structure, the all-solid secondary battery 1 mayhave further improved energy density and thermal stability.

The cathode active material may be covered with a coating layer asdescribed above. The coating layer may be any suitable coating layer forcathode active materials of all-solid secondary batteries. The coatinglayer may include, for example, Li₂O—ZrO₂.

When the cathode active material includes, for example, a ternarylithium transition metal oxide including Ni, such as NCA or NCM, theall-solid secondary battery 1 may have an increased capacity density andelusion of metal ion from the cathode active material may be reduced ina charged state. As a result, the all-solid secondary battery 1 may haveimproved cycle characteristics.

The cathode active material may be in the form of particles having, forexample, a true-spherical particle shape or an oval-spherical particleshape. The particle diameter of the cathode active material is notparticularly limited, and may be in a range applicable to a cathodeactive material of an all-solid secondary battery. An amount of thecathode active material in the cathode layer 10 is not particularlylimited, and may be in a range applicable to a cathode active materialof an all-solid secondary battery.

The cathode layer 10 may further include, in addition to a cathodeactive material and a solid electrolyte as described above, anadditive(s), for example, a conducting agent, a binder, a filler, adispersing agent, an auxiliary ionic conducting agent, or the like. Theconducting agent may be, for example, graphite, carbon black, acetyleneblack, Ketjen black, carbon fibers, metal powder, or the like. Thebinder may be, for example, a styrene-butadiene rubber (“SBR”),polytetrafluoroethylene (“PTFE”), polyvinylidene fluoride (“PVDF”),polyethylene, polyarcrylate resin, or the like. The dispersing agent,the auxiliary ionic conducting, the filler, or the like which may beadded to the cathode layer 10 may be any suitable materials for use in acathode of an all-solid secondary battery.

According to another aspect of the disclosure, a method of manufacturingan all-solid secondary battery includes: providing an anode layer;providing a cathode layer; providing a solid electrolyte layer betweenthe anode layer and the cathode layer to thereby prepare a laminate; andpressing the laminate. The all-solid secondary battery may have improvedcycle characteristics.

Hereinafter, embodiments of the method will be described with referenceto FIGS. 1 to 3. The all-solid secondary battery 1 according to anembodiment may be manufactured by forming the cathode layer 10, theanode layer 20, and the solid electrolyte layer 30 and then laminatingthem on one another.

Formation of Anode Layer

For example, an anode active material, an ionic compound, and a binder,as ingredients of the first anode active material layer 22, may be addedto a polar solvent or a non-polar solvent to prepare a slurry. Theprepared slurry may be coated on the anode current collector 21 and thendried to prepare a first laminate. Subsequently, the dried firstlaminate may be pressed to thereby form the anode layer 20. The pressingmay be performed using any suitable method, and is not limited to aspecific method, for example, the pressing may be roll pressing or flatpressing. The pressing may be omitted.

The ionic compound may include a binary compound, a ternary compound, ora combination thereof as described above. The ionic compound may notinclude a plurality of sulfur (S) atoms. The ionic compound may notinclude sulfur (S) and phosphorous (P) atoms at the same time.

Formation of Cathode Layer

For example, a cathode active material, a conducting agent, a solidelectrolyte, and a binder, as ingredients of the cathode active materiallayer 12, may be added to a non-polar solvent to prepare a slurry. Theprepared slurry may be coated on the cathode current collector 11 andthen dried to form a laminate. The obtained laminate may be pressed tothereby form the cathode layer 10. The pressing may be performed usingany suitable method, and is not limited to a specific method, forexample, the pressing may be roll pressing, flat pressing, or isostaticpressing. The pressing may be omitted. In an embodiment, the cathodelayer 10 may be formed by compaction molding a mixture of theingredients of the cathode active material layer 12 into pellets orextending the mixture into a sheet form, in which case, the cathodecurrent collector 11 may be omitted.

Formation of Solid Electrolyte Layer

The solid electrolyte layer 30 may be formed using a solid electrolyte,for example, a sulfide-based solid electrolyte.

The sulfide-based solid electrolyte may be prepared by treatment of astarting, e.g., source, material with, for example, melt quenching ormechanical milling. However, embodiments are not limited thereto. Anysuitable method of preparing a sulfide-based solid electrolyte may beused. For example, in the case of using melt quenching, afterpredetermined amounts of source materials such as Li₂S and P₂S₅ aremixed together and then made into pellets, the pellets may be subjectedto reaction at a predetermined reaction temperature under inert gas (forexample, Ar) or hydrogen sulfide (H₂S) or vacuum conditions and thenquenched to thereby prepare a sulfide-based solid electrolyte. Thereaction temperature of the mixture of Li₂S and P₂S₅ may be, forexample, about 200° C. to about 400° C., or about 250° C. to about 300°C. The reaction time may be, for example, about 0.1 hours to about 12hours, or about 1 hour to about 12 hours. The quenching temperature ofthe reaction product may be about 10° C. or less or about 0° C. or less,and the quenching rate may be about 1° C./second (sec) to about 10,000°C./sec, or about 1° C./sec to about 1,000° C./sec. For example, in thecase of using mechanical milling, the source materials such as Li₂S andP₂S₅ may be reacted while stirring using, for example, a ball mill, tothereby prepare a sulfide-based solid electrolyte. The stirring rate andstirring time in the mechanical milling are not specifically limited.The higher the stirring rate, the production rate of the sulfide-basedsolid electrolyte may become higher. The longer the stirring time, therate of conversion of the source material into the sulfide-based solidelectrolyte may become higher. Then, the mixture of the sourcematerials, obtained by melting quenching or mechanical milling, may bethermally treated at a predetermined temperature and then grinded tothereby prepare a solid electrolyte in the form of particles. When thesolid electrolyte has glass transition characteristics, the solidelectrolyte may be converted from an amorphous form to a crystallineform by thermal treatment.

The solid electrolyte obtained through such a method as described abovemay be deposited using a film formation method, for example, an aerosoldeposition method, a cold spraying method, or a sputtering method, tothereby prepare the solid electrolyte layer 30. In an embodiment, thesolid electrolyte layer 30 may be prepared by pressing solid electrolyteparticles alone. In an embodiment, the solid electrolyte layer 30 may beformed by mixing a solid electrolyte, a solvent, and a binder togetherto obtain a mixture, and coating, drying, and then pressing the mixture.

Manufacture of all-Solid Secondary Battery

The cathode layer 10, the anode layer 20, and the solid electrolytelayer 30, which are formed according to the above-described methods, maybe stacked such that the solid electrolyte layer 30 is interposedbetween the cathode layer 10 and the anode layer 20, and then be pressedto thereby manufacture the all-solid secondary battery 1.

For example, the solid electrolyte layer 30 may be arranged on thecathode layer 10 to thereby prepare a second laminate. Subsequently, theanode layer 20 may be arranged on the second laminate such that thefirst anode active material layer 22 contacts the solid electrolytelayer 30 to thereby prepare a third laminate. The third laminate maythen be pressed to thereby manufacture the all-solid secondary battery1. The pressing may be performed, for example, at a temperature of aboutroom temperature to about 90° C., or a temperature of about 20° C. toabout 90° C. In an embodiment, the pressing may be performed at a hightemperature of about 100° C. or greater. The pressing time may be, forexample, about 30 minutes or less, about 20 minutes or less, about 15minutes or less, or about 10 minutes or less. For example, the pressingtime may be about 1 milliseconds (ms) to about 30 minutes, about 1 ms toabout 20 minutes, about 1 ms to about 15 minutes, or about 1 ms to about10 minutes. The pressing method may be, for example, isostatic pressing,roll pressing, or flat pressing. However, embodiments are not limitedthereto. Any suitable pressing method may be used. A pressure applied inthe pressing may be, for example, about 500 megapascals (MPa) or less,about 480 MPa or less, about 450 MPa or less, about 400 MPa or less,about 350 MPa or less, about 300 MPa or less, about 250 MPa or less,about 200 MPa or less, about 150 MPa or less, or about 100 MPa or less.For example, the pressure applied in the pressing may be about 50 MPa toabout 500 MPa, about 50 MPa to about 480 MPa, about 50 MPa to about 450MPa, about 50 MPa to about 400 MPa, about 50 MPa to about 350 MPa, about50 MPa to about 300 MPa, about 50 MPa to about 250 MPa, about 50 MPa toabout 200 MPa, about 50 MPa to about 150 MPa, or about 50 MPa to about100 MPa. Through the pressing under the above-described conditions, forexample, the solid electrolyte particles may be sintered to thereby forma single solid electrolyte layer.

Although the constitutions of the all-solid secondary battery 1 and themethods of manufacturing the all-solid secondary battery 1 are describedabove as embodiments, the disclosure is not limited thereto, and theconstituent members of the all-solid secondary battery and themanufacturing processes may be appropriately varied.

One or more embodiments of the disclosure will now be described indetail with reference to the following examples. However, these examplesare only for illustrative purposes and are not intended to limit thescope of the one or more embodiments of the disclosure.

Example 1: LiCl 10 Weight Percent (Wt %), 100 Megapascals (MPa),Lithium-Phosphorous-Sulfur (“LPS”)+Argyrodite Formation of Anode Layer

A nickel (Ni) foil having a thickness of about 10 micrometers (μm) wasprepared as an anode current collector. Furnace black (“FB-C”) having aprimary particle diameter of about 76 nanometers (nm) and silver (Ag)particles having an average particle diameter of about 60 nm wereprepared as anode active materials. Lithium chloride (LiCl) powder wasprepared as an ionic compound.

Mixed powder of furnace black (“FB-C”) and silver particles in a weightratio of about 3:1, and lithium chloride powder were used to form ananode layer. Specifically, anhydrous lithium chloride powder was addedinto a container including N-methyl-2-pyrrolidone (“NMP”) and then mixedwhile stirring with a Thinky mixer at about 1300 revolutions per minute(rpm) for about 5 minutes to prepare a first solution. A poly(vinylidenefluoride-co-hexafluoropropylene) (“PVDF-HFP”) copolymer binder (PVDF#9300, available from KUREHA) was added to the first solution and thendissolved to prepare a second solution. The mixed powder of furnaceblack (“FB-C”) and silver particles in a weight ratio of 3:1 was addedto the second solution and then mixed with stirring to thereby prepare aslurry. The prepared slurry was coated on a Ni foil with a blade coaterand then dried in the air at about 80° C. for about 20 minutes. Theresulting laminate was vacuum-dried at about 40° C. for about 10 hours.The dried laminate was roll-pressed to planarize a surface of a firstanode active material layer of the laminate. Through the above-describedprocess, an anode layer was formed. The first anode active materiallayer in the anode layer had a thickness of about 5 μm.

In the first anode active material layer, an amount of the lithiumchloride was about 10 wt %, and an amount of the binder was about 6 wt%.

Formation of Cathode Layer

Li₂O—ZrO₂ (“LZO”)-coated LiNi_(0.8)Co_(0.15)Mn_(0.05)O₂ (“NCM”) wasprepared as a cathode active material. The LZO-coated cathode activematerial was prepared according to a method disclosed in KR10-2016-0064942. Argyrodite-type crystalline Li₆PS₅Cl powder wasprepared as a solid electrolyte. A polytetrafluoroethylene (“PTFE”)binder (Teflon binder, available from DuPont) was prepared. Carbonnanofibers (“CNF”) and furnace black (“FB-C”) were prepared asconducting agents. The cathode active material, the solid electrolyte,the CNF (conducting agent), the FB-C (conducting agent), and the binderwere mixed together in a weight ratio of about 84.2:11.5:1.9:0.9:1.5 toobtain a mixture. This mixture was formed into a large sheet by molding,to thereby form a cathode sheet. The cathode sheet was arranged on acarbon-coated aluminum foil having a thickness of about 18 μm used as acathode current collector and then pressed to thereby form a cathodelayer. A cathode active material layer in the cathode layer had athickness of about 150 μm.

Preparation of Solid Electrolyte Powder

A mixture of lithium sulfide-type crystalline Li₇P₃S₁₁ powder andargyrodite-type crystalline Li₆PS₅Cl powder in a weight ratio of 50:50was prepared. The mixture was stirred with addition of xylene to therebyprepare a slurry. The slurry was dried in the air at about 80° C. forabout 60 minutes to obtain a dried product. The dried product wasfurther vacuum-dried at about 40° C. for about 10 hours. Through theabove-described processes, solid electrolyte powder was prepared.

Manufacture of all-Solid Secondary Battery

250 milligrams (mg) of the solid electrolyte powder was applied onto theanode layer and then planarized to thereby form a solid electrolytelayer. The cathode layer prepared as described above was arranged on thesolid electrolyte layer to form a laminate. The laminate was thentreated by plate pressing under a pressure of about 100 MPa at about 25°C. for about 10 minutes to thereby manufacture an all-solid secondarybattery. Through the pressing, the solid electrolyte layer was sintered,and characteristics of the all-solid secondary battery were improved.

Example 2: LiCl 10 wt %, 500 MPa, LPS+Argyrodite

An all-solid secondary battery was manufactured in the same manner as inExample 1, except that the pressure applied to the laminate in themanufacturing of the all-solid secondary battery was varied to about 500MPa.

Example 3: LiCl 10 wt %, 500 MPa, Argyrodite Alone

An all-solid secondary battery was manufactured in the same manner as inExample 1, except that argyrodite-type crystalline Li₆PS₅Cl powder wasused alone as the solid electrolyte powder for the solid electrolytelayer, and the pressure applied to the laminate in the manufacturing ofthe all-solid secondary battery was varied to about 500 MPa.

Example 4: LiCl 10 wt %, 500 MPa, LPS Alone

An all-solid secondary battery was manufactured in the same manner as inExample 1, except that lithium sulfide-type crystalline Li₇P₃S₁₁ powderwas used alone as the solid electrolyte powder for the solid electrolytelayer, and the pressure applied to the laminate in the manufacturing ofthe all-solid secondary battery was varied to about 500 MPa.

Example 5: LiCl 3 wt %, 500 MPa, LPS Alone

An all-solid secondary battery was manufactured in the same manner as inExample 4, except that the amount of LiCl was changed to 3 wt %.

Example 6: LiCl 6 wt %, 500 MPa, LPS Alone

An all-solid secondary battery was manufactured in the same manner as inExample 4, except that the amount of LiCl was changed to 6 wt %.

Example 7: LiCl 15 wt %, 500 MPa, LPS Alone

An all-solid secondary battery was manufactured in the same manner as inExample 4, except that the amount of LiCl was changed to 15 wt %.

Example 8: LiCl 20 wt %, 500 MPa, LPS Alone

An all-solid secondary battery was manufactured in the same manner as inExample 4, except that the amount of LiCl was changed to 20 wt %.

Example 9: LiCl 30 wt %, 500 MPa, LPS Alone

An all-solid secondary battery was manufactured in the same manner as inExample 4, except that the amount of LiCl was changed to 30 wt %.

Example 10: LiCl 40 wt %, 500 MPa, LPS Alone

An all-solid secondary battery was manufactured in the same manner as inExample 4, except that the amount of LiCl was changed to 40 wt %.

Example 11: LiCl 50 wt %, 500 MPa, LPS Alone

An all-solid secondary battery was manufactured in the same manner as inExample 4, except that the amount of LiCl was changed to 50 wt %.

Example 12: LiCl 80 wt %, 500 MPa, LPS Alone

An all-solid secondary battery was manufactured in the same manner as inExample 4, except that the amount of LiCl was changed to 80 wt %.

Example 13: Use of Sn Thin Film

A Ni foil having a thickness of about 10 μm was prepared as an anodecurrent collector. Then, a tin (Sn)-plated thin film having a thicknessof about 500 nm was formed on the Ni foil. Then, an all-solid secondarybattery was manufactured in the same manner as in Example 3, except thatthe Ni foil having the Sn thin film was used as an anode currentcollector.

Example 14: FB-C Alone

An all-solid secondary battery was manufactured in the same manner as inExample 3, except that furnace black (“FB-C”) was used alone as theanode active material, instead of the mixture of furnace black (“FB-C”)having a primary particle diameter of about 76 nm and silver (Ag)particles having an average particle diameter of about 60 nm in a weightratio about 3:1.

Example 15: Si Alone

An all-solid secondary battery was manufactured in the same manner as inExample 3, except that silicon (Si) particles having an average particlediameter of about 100 nm were used alone as the anode active material,instead of the mixture of furnace black (“FB-C”) having a primaryparticle diameter of about 76 nm and silver (Ag) particles having anaverage particle diameter of about 60 nm in a weight ratio about 3:1.

Comparative Example 1: LiCl 0 wt %, 500 MPa, LPS Alone

An all-solid secondary battery was manufactured in the same manner as inExample 4, except that LiCl was not added in the first anode activematerial layer, and the pressure applied to the laminate in themanufacturing of the all-solid secondary battery was varied to about 500MPa.

Comparative Example 2: LiCl 0 wt %, 100 MPa, Argyrodite Alone

An all-solid secondary battery was manufactured in the same manner as inExample 3, except that LiCl was not added in the first anode activematerial layer and the pressure applied to the laminate in themanufacturing of the all-solid secondary battery was varied to about 100MPa,

Comparative Example 3: No Use of First Anode Active Material Layer

An all-solid secondary battery was manufactured in the same manner as inExample 3, except that only the Ni anode current collector was usedwithout the formation of the first anode active material layer.

Comparative Example 4: Ni Alone, LiCl 0 wt %

An all-solid secondary battery was manufactured in the same manner as inExample 3, except that nickel (Ni) particles having an average particlediameter of about 100 nm were used alone, instead of the mixture offurnace black (“FB-C”) having a primary particle diameter of about 76 nmand silver (Ag) particles having an average particle diameter of about60 nm in a weight ratio about 3:1, and LiCl was not added.

Comparative Example 5: Graphite Alone, LiCl 0 wt %

An all-solid secondary battery was manufactured in the same manner as inExample 3, except that scaly graphite particles having an averageparticle diameter of about 5 μm were used alone as the anode activematerial, instead of the mixture of furnace black (“FB-C”) having aprimary particle diameter of about 76 nm and silver (Ag) particleshaving an average particle diameter of about 60 nm in a weight ratioabout 3:1, and LiCl was not added.

Evaluation Example 1: Elastic Modulus Measurement

The mixture of sulfide-type crystalline Li₇P₃S₁₁ powder andargyrodite-type crystalline Li₆PS₅Cl powder in a weight ratio of 50:50,which was used in Example 1, was pressed under an isostatic pressure ofabout 500 MPa at about 25° C. for about 10 minutes to thereby preparefirst pellets.

The lithium sulfide-type crystalline Li₇P₃S₁₁ powder, which was used inExample 4, was pressed under an isostatic pressure of about 500 MPa atabout 25° C. for about 10 minutes to thereby prepare second pellets.

An elastic modulus of each of the pellet samples was measured using a TI980 10 (available BRUKER). The elastic modulus is also called Young'smodulus.

A storage modulus at a contact depth of about 200 nm was taken as anelastic modulus. The measurement results are shown in Table 1.

TABLE 1 Samples Elastic modulus (gigapascals (GPa)) Li₇P₃S₁₁ + Li₆PS₅Cl26.5 (mixture in a weight ratio of 50:50) Li₇P₃S₁₁ alone 22.5

Referring to Table 1, as a result of the elastic modulus measurement,the solid electrolytes used in Examples 1 and 4 were found to have a lowelastic modulus of about 30 GPa or less.

Accordingly, when the solid electrolyte of Example 1 or Example 4 isused in manufacturing an all-solid secondary battery, a reduced pressuremay be applied.

Evaluation Example 2: Charge-Discharge Test

Charge-discharge characteristics of each of the all-solid secondarybatteries manufactured in Examples 1 to 12 and Comparative Examples 1 to5 were evaluated by a charge-discharge test as follows. Thecharge-discharge test of the all-solid secondary batteries was performedin a 60° C.-thermostatic bath.

At a 1^(st) cycle, each all-solid secondary battery was charged with aconstant current of 0.1 C for about 12.5 hours until a battery voltagereached 4.25 volts (V), and then discharged with a constant current of0.1 C until a battery voltage reached 3.0 V.

Some of the charge-discharge test results are represented in Table 2.The charge-discharge efficiency in Table 2 is defined as Equation 1.

Charge-discharge efficiency (%)=(Discharge capacity/Chargecapacity)×100  Equation 1

TABLE 2 Example Charge-discharge efficiency (percent (%)) Example 1 67.0Example 2 91.4 Example 3 91.7 Example 4 89.1 Example 5 55.4 Example 670.0 Example 7 86.3 Example 8 82.0 Example 9 70.5 Example 10 67.7Example 11 58.5 Example 12 54.2 Comparative Example 1 47.4 ComparativeExample 2 31.0

The all-solid secondary batteries of Examples 1 to 12 were found to haveimproved charge-discharge efficiencies, as compared with the all-solidsecondary batteries of Comparative Examples 1 and 2, due to theinclusion of LiCl as the ionic compound in the first anode activematerial layer in Examples 1 to 12.

In the all-solid secondary batteries of Examples 11 and 12, including 50wt % or greater of LiCl, due to partial precipitation of LiCl from theslurry, the processability in preparing and coating the slurry wasdeteriorated, and film characteristic of the first anode active materiallayer was partially non-uniform. Accordingly, the all-solid secondarybatteries of Examples 11 and 12 had relatively poor cyclecharacteristics than the all-solid secondary batteries of Examples 4, 6to 10.

Such a low charge-discharge efficiency of the all-solid secondarybattery of Comparative Example 1 is attributed to increased sidereactions at between the first anode active material layer and the solidelectrolyte layer.

The low charge-discharge efficiency of the all-solid secondary batteryof Comparative Example 2 is attributed to an increased interfacialresistance between the solid electrolyte particles, which may be causedby insufficient sintering of the solid electrolyte particles under arelatively low pressing pressure of 100 MPa with respect to a highelastic modulus of the argyrodite-type solid electrolyte used in theall-solid secondary battery of Comparative Example 2.

The all-solid secondary batteries of Examples 13 to 15 were found tonormally operate during the 1^(st) charge-discharge cycle, while ashort-circuit occurred in the all-solid secondary batteries ofComparative Examples 3 to 5 during the 1^(st) charge discharge cycle.

After completion of charging at the 1^(st) cycle, cross-sections of theall-solid secondary batteries of Examples 1 to 12, 14, and 15 wereanalyzed using scanning electron microscopy (“SEM”). As a result, it wasfound that a lithium metal layer corresponding to a second anode activematerial layer was formed between the first anode active material layerand the anode current collector.

After completion of charging at the 1^(st) cycle, a cross-section of theall-solid secondary battery of Example 13 was analyzed using SEM. As aresult, it was found that a lithium metal layer corresponding to asecond anode active material layer was formed between the first anodeactive material layer and the Sn thin film.

As described above, the all-solid secondary battery according to anembodiment may be applicable in different types of portable devices orvehicles.

As described above, according to an embodiment, an all-solid secondarybattery may have improved cycle characteristics by inclusion of an ioniccompound in a first anode active material layer.

It should be understood that embodiments described herein should beconsidered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

While one or more embodiments have been described with reference to thefigures, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope as defined by the following claims.

What is claimed is:
 1. An all-solid secondary battery comprising: ananode comprising an anode current collector and a first anode activematerial layer; a cathode comprising a cathode active material layer;and a solid electrolyte layer between the anode and the cathode, whereinthe first anode active material layer comprises an anode active materialand an ionic compound, wherein the ionic compound comprises a binarycompound, a ternary compound, or a combination thereof, and wherein theionic compound does not comprise a plurality of sulfur atoms.
 2. Theall-solid secondary battery of claim 1, wherein the ionic compound is aninorganic compound.
 3. The all-solid secondary battery of claim 1,wherein the ionic compound is a crystalline compound or an amorphouscompound.
 4. The all-solid secondary battery of claim 1, wherein theionic compound comprises a binary compound, and the binary compound hasa rocksalt-type structure, a wurtzite-type structure, an antifluoritestructure, or a hexagonal structure, the ionic compound comprises aternary compound, and the ternary compound has a crystal structure of anantiperovskite-type structure, a layered-type structure, a spinel-typestructure, or a trigonal structure, or a combination thereof.
 5. Theall-solid secondary battery of claim 1, wherein the ionic compound is alithium salt compound.
 6. The all-solid secondary battery of claim 5,wherein the lithium salt compound comprises an anion having an ionicradius of greater than 0 nanometers to about 0.40 nanometers.
 7. Theall-solid secondary battery of claim 5, wherein the lithium saltcompound comprises: a binary compound, wherein the binary compoundcomprises LiF, LiCl, LiBr, LiI, LiH, Li₂S, Li₂O, Li₂Se, Li₂Te, Li₃N,Li₃P, Li₃As, Li₃Sb, LiB₃, or a combination thereof; a ternary compound,wherein the ternary compound comprises Li₃OCl, LiPF₆, LiBF₄, LiSbF₆,LiAsF₆, LiClO₄, LiAlO₂, LiAlCl₄, LiNO₃, Li₂CO₃, LiBH₄, Li₂SO₄, Li₃BO₃,Li₃PO₄, Li₄NCl, Li₅NCl₂, Li₃BN₂, or a combination thereof, or acombination thereof.
 8. The all-solid secondary battery of claim 5,wherein the lithium salt compound comprises LiF, LiCl, LiBr, LiI, or acombination thereof.
 9. The all-solid secondary battery of claim 5,wherein the lithium salt compound is not a composite with a sulfide, anoxide, or a combination thereof.
 10. The all-solid secondary battery ofclaim 1, wherein an amount of the ionic compound is about 3 weightpercent to about 50 weight percent, based on a total weight of the firstanode active material layer.
 11. The all-solid secondary battery ofclaim 1, wherein an amount of the ionic compound is about 3 weightpercent to about 30 weight percent, based on a total weight of the firstanode active material layer.
 12. The all-solid secondary battery ofclaim 1, wherein the anode active material is in a particulate form, andthe anode active material has an average particle diameter of greaterthan 0 micrometers to about 4 micrometers.
 13. The all-solid secondarybattery of claim 1, wherein the anode active material comprises acarbonaceous anode active material, a metal anode active material, ametalloid anode active material, or a combination thereof.
 14. Theall-solid secondary battery of claim 12, wherein the anode activematerial comprises the carbonaceous anode active material and thecarbonaceous anode active material comprises amorphous carbon.
 15. Theall-solid secondary battery of claim 12, wherein the anode activematerial comprises the metal anode active material or the metalloidanode active material, and the metal anode active material or themetalloid anode active material comprises gold, platinum, palladium,silicon, silver, aluminum, bismuth, tin, antimony, magnesium, zinc, or acombination thereof.
 16. The all-solid secondary battery of claim 1,wherein the anode active material comprises a mixture of a firstparticle comprising amorphous carbon, and a second particle comprising ametal, metalloid, or a combination thereof, and an amount of the secondparticle is about 8 weight percent to about 60 weight percent, based ona total weight of the mixture.
 17. The all-solid secondary battery ofclaim 1, wherein the first anode active material layer further comprisesa binder.
 18. The all-solid secondary battery of claim 1, wherein athickness of the first anode active material layer is about 50% or lessof a thickness of the cathode active material layer, and the first anodeactive material layer has a thickness of about 1 micrometer to about 20micrometers.
 19. The all-solid secondary battery of claim 1, furthercomprising a film on the anode current collector, wherein the filmcomprises an element alloyable with lithium, and wherein the film islocated between the anode current collector and the first anode activematerial layer.
 20. The all-solid secondary battery of claim 19, whereinthe film has a thickness of about 1 nanometer to about 800 nanometers.21. The all-solid secondary battery of claim 1, further comprising asecond anode active material layer between the anode current collectorand the solid electrolyte layer, wherein the second anode activematerial layer is a metal layer comprising lithium, r a lithium alloy,or a combination thereof.
 22. The all-solid secondary battery of claim21, wherein the second anode active material layer is between the anodecurrent collector and the first anode active material layer, between thesolid electrolyte layer and the first anode active material layer,within the first anode active material layer, or a combination thereof.23. The all-solid secondary battery of claim 1, wherein the anodecurrent collector, the first anode active material layer, and a regionbetween the anode current collector and the solid electrolyte layer donot comprise lithium or a lithium alloy.
 24. The all-solid secondarybattery of claim 1, wherein the anode current collector is directly onthe first anode active material layer, and the first anode activematerial layer is directly on the solid electrolyte layer.
 25. Theall-solid secondary battery of claim 1, wherein the solid electrolytelayer comprises a sulfide solid electrolyte.
 26. The all-solid secondarybattery of claim 25, wherein the sulfide solid electrolyte comprisesLi₂S—P₂S₅, Li₂S—P₂S₅—LiX, wherein X is a halogen, Li₂S—P₂S₅—Li₂O,Li₂S—P₂S₅—Li₂O—LiI, Li₂S—SiS₂, Li₂S—SiS₂—LiI, Li₂S—SiS₂—LiBr,Li₂S—SiS₂—LiCl, Li₂S—SiS₂—B₂S₃—LiI, Li₂S—SiS₂—P₂S₅—LiI, Li₂S—B₂S₃,Li₂S—P₂S₅—Z_(m)S_(n), wherein m and n are each independently a positivenumber, and Z is Ge, Zn, or Ga, Li₂S—GeS₂, Li₂S—SiS₂—Li₃PO₄,Li₂S—SiS₂—Li_(p)MO_(q), wherein p and q are each independently apositive number, and M is P, Si, Ge, B, Al, Ga, or In, or a combinationthereof.
 27. The all-solid secondary battery of claim 25, wherein thesulfide solid electrolyte comprises Li₇P₃S₁₁, Li₇PS₆, Li₄P₂S₆, Li₃PS₆,Li₃PS₄, Li₂P₂S₆, or a combination thereof.
 28. The all-solid secondarybattery of claim 25, wherein the sulfide solid electrolyte comprises alithium argyrodite solid electrolyte represented by Formula 1:Li⁺ _(12-n-x)A^(n+)X²⁻ _(6-x)Y¹⁻ _(x)  Formula 1 wherein, in Formula 1,0≤x≤2, A is P, As, Ge, Ga, Sb, Si, Sn, Al, In, Ti, V, Nb, or Ta, X is S,Se, or Te, and Y′ is Cl, Br, I, F, CN, OCN, SCN, or N₃, and n is avalence of A.
 29. The all-solid secondary battery of claim 28, whereinthe lithium argyrodite solid electrolyte comprisesLi_(7-x)PS_(6-x)Cl_(x), wherein 0≤x≤2, Li_(7-x)PS_(6-x)Br_(x), wherein0≤x≤2, Li_(7-x)PS_(6-x)I_(x), wherein 0≤x≤2, or a combination thereof.30. The all-solid secondary battery of claim 1, wherein the solidelectrolyte layer comprises a solid electrolyte having an elasticmodulus of about 15 gigapascals to about 35 gigapascals.
 31. A method ofmanufacturing an all-solid secondary battery, the method comprising:providing an anode; providing a cathode; providing a solid electrolytelayer between the anode and the cathode to thereby prepare a laminate;and pressing the laminate to manufacture the all-solid secondarybattery, wherein the anode comprises an anode current collector and afirst anode active material layer, the first anode active material layercomprises an anode active material and an ionic compound, the ioniccompound comprises a binary compound, a ternary compound, or acombination thereof, and the ionic compound does not comprise aplurality of sulfur atoms.
 32. The method of claim 31, wherein thepressing is performed at a temperature in a range of about 20° C. toabout 90° C. for about 1 millisecond to about 30 minutes.
 33. The methodof claim 31, wherein the pressing comprises cold isostatic pressing,roll pressing, or flat pressing.
 34. The method of claim 31, wherein, inthe pressing, a pressure of greater than 0 megapascals to about 500megapascals is applied to the laminate.
 35. The method of claim 31,wherein the ionic compound does not comprise phosphorous and sulfur atthe same time.
 36. An all-solid secondary battery comprising: an anodecomprising an anode current collector and a first anode active materiallayer, wherein the first anode active material layer comprises an anodeactive material and an ionic compound, wherein the ionic compoundcomprises LiF, LiCl, LiBr, LiI, LiH, Li₂S, Li₂O, Li₂Se, Li₂Te, Li₃N,Li₃P, Li₃As, Li₃Sb, LiB₃, or a combination thereof, and optionallyLi₃OCl, LiPF₆, LiBF₄, LiSbF₆, LiAsF₆, LiClO₄, LiAlO₂, LiAlCl₄, LiNO₃,Li₂CO₃, LiBH₄, Li₂SO₄, Li₃BO₃, Li₃PO₄, Li₄NCl, Li₅NCl₂, Li₃BN₂, or acombination thereof, and wherein an amount of the ionic compound isabout 3 weight percent to about 30 weight percent, based on a totalweight of the first anode active material layer; a cathode comprising acathode active material layer; and a solid electrolyte layer between theanode and the cathode, wherein the solid electrolyte layer comprisesLi₇P₃S₁₁, Li₇PS₆, Li₄P₂S₆, Li₃PS₆, Li₃PS₄, Li₂P₂S₆, or a combinationthereof, and optionally Li_(7-x)PS_(6-x)Cl_(x), wherein 0≤x≤2,Li_(7-x)PS_(6-x)Br_(x), wherein 0≤x≤2, Li_(7-x)PS_(6-x)I_(x), wherein0≤x≤2, or a combination thereof.